Internal combustion engines create heat through combustion, friction and various component inefficiencies. A cooling system regulates the temperature of the engine to protect the engine from excessive heat and to promote efficient combustion. A cold engine may be less efficient and may produce increased emissions. An overly hot engine increases stress on engine components and may cause mechanical failures.
The internal combustion engine typically operates more efficiently when regions within the engine are maintained at different temperatures. For example, the engine may benefit from a lower temperature in the bottom of the engine relative to the top of the engine. To maintain different temperatures in the regions of the engine, traditional cooling systems typically employ multiple sensors that measure and track metal temperatures in the engine. It can be appreciated that measuring metal temperatures in a mass production engine can be complex and costly. For example, any additional sensors increase production costs, add to engine complexity and increase vehicle warranty costs.